Humidostat



July 25, 1933. c. F. WARRICK HUMIDOS TAT Filed May 18, 1931 2 Sheets-Sheet l v INVENTOR I Ciard asfii arrzc/f ATTORNEYS y 25, c. F. WARRICK 1,920,043

HUMIDOSTAT Filed May 18, 1931 2 Sheets-Sheet 2 Ciard K714222 31? T9 BY ATTORNEY-S Patented July 25, 1933 UNITED STATES PATENT OFFICE A CHLARLES F. WARRICK, 0F DETROIT, MICHIGAN, ASSIGNOR T0 WHITEHEAD & KALES COMPANY, OF RIVER ROUGE, MICHIGAN, A CORPORATION OF MICHIGAN HUMIDOSTAT Application filed May 18, 1931.

This invention relates generally to humidostats and more particularly to a construction and arrangement of parts tending to render more efficient and improve generally devices of this character.

The invention contemplates obtaining a more accurate reading and otherwise improving the operation of humidostats by providing a hygroscopic device so constructed as to be sensitive solely to variations in humidity and also one in which the action thereof is not impaired by temperature changes.

Another advantageous feature of this invention which contpibutes materially to the commercial value and acceptability of the humidostat resides in the provision of means incorporated in the device as a unit therewith for visibly indicating upon a scale the percent of relative humidity at all times.

A further object of the present invention is to provide the humidostat with actuating means adjustable for operating a humidifier in accordance with various predetermined percentages of relative humidity, together with means for visibly indicating upon the scale above mentioned the percent of relative humidity at which the actuating means aforesaid is set for operation.

In addition to the foregoing, the present invention contemplates improvement in the construction of hygroscopic devices which will be made more apparent as this description proceeds, especially when considered in connection with the accompanying drawings wherein: l

Figure 1 is a top plan view of a humidostat constructed in accordance with this invention;

Figure 2 is a cross-sectional view taken on the line 2-2 of Figure 1;

Figure 3 is a top plan view of the humidostat with certain parts of the casing broken away for the sake of clearness;

Figure 4 is a plan view of the hygroscopic device shown in Figure 2;

Figure 5 is a section taken on the line 5-5 of Figure 2 with the casing removed.

Referring now to the drawings, it will be noted that there is illustrated in Figure 1 a Serial No. 538,307.

humidostat assembly 10 comprising a casing 11 having apertured annular side walls 12 and having a transparent top wall 13 secured at the periphery thereof to the side walls in any suitable manner. Arranged within the casing 11 is an arcuate hygroscopic responsive device 14 having one end rigidly secured to a bracket 15 extending upwardly from the base 17 of the casing and having the opposite end connected to the outer end of a suitable arm 16 by means of a coil spring 18. The arm 16 is journaled intermediate the ends thereof upon a suitable vertical shaft 19 having the opposite ends respectively journaled in the base 17 and in a bracket 20 secured to and positioned substantially above the base. The inner end of the arm is preferably in the form of an arcuate rack 21 adapted to meshwith a pinion 22 which in turnis secured to a second vertical shaft 23 also journaled within the base 17 and bracket 20. The shaft 23 is preferably arranged centrally of the annular casing and the upper end thereof projects" above the bracket 2() a sufficient distance for receiving the contact disk 24 and pointer 25. The contact disk 24 is journaled in any suitable manner upon the shaft 23 for rotation relative thereto and is provided with a pair of spring contact blades 26 insulated from each other and connected by suitable flexible conductors 27 to the circuit for controlling the actuation of the humidifier (not shown).

The pointer 25 is rigidly secured to the extreme upper end of the shaft 23 so as to rotate therewith and one end thereof extends over a suitable dial 28 for directly indicating the degree of humidity through the transparent wall'13 of the housing. The tail of the pointer is provided with a contact 29 adapted in one osition thereof to bridge the contacts26 or completing the circuit to the humidifier. Thus, it w1ll be seen that the pointer performs a dual function in the apparatus since it not only indicates the degree of humidity, but also makes and breaks the circuit to the humidifier.

It will further be observed from the previous description that the pointer 25 is connected to the hygroscopic device in such a manner that movement of the latter by vari ations in moisture content of the hygroscopic element causes a correspom'ling movement of the pointer over the dial and since the contact- 29 is carried by the pointer, itfollows that the circuit to the humidostat will be automatically completed and broken depending upon the moisture content of the hygroscopic device. i

In order to vary the degree of humidity at which the pointer functions to control the circuit to the humidostat, the contact disk 24 is preferably adjustably mounted upon the shaft 23 so that the same may be rotated to vary the position of the contacts 96 relative to the pointer. For adjusting the disk, I provide a suitable handle 30 having a portion rigidly secured to the disk and having another portion 31 extending through an arcuate slot 32 in the side wall 12 of the casing. In order to conveniently and readily predetermine the percentage of relative humidity at which it is desirable to have the device function, I provide a second pointer 84 having the inner end rigidly secured to the disk and having the outer end overlapping the dial below the pointer 25. Thus, it will be seen that by accurately positioning the contacts 26 relative to the pointer 34, the device may be readily and accurately adjusted by merely rotating the contact disk relative to the pointers 25 to the desired positions indicated on "the dial by the pointer 34. a

As previously stated, it is one of the principal objects of this invention to provide a hygroscopic device operated solely by variations in the moisture content of the hygroscopic section or, in other words, so constructed that changes in temperature will not impair the accuracy thereof. For accomplishing the foregoing result, the hygroscopically responsive device 14 is formed of two sections which are preferably fashioned from the same material, but are relatively responsive and non-responsive to moisture variations. In detail, the hygroscopic device 14 comprises two arcuate sections 36 and 37 rigidly secured together in contacting relation and arranged substantially concentric with the axis of the casing. Both of the sections 36 and 37 are formed of the same absorbent material having the property of expanding and contracting as the moisture content thereof increases or decreases. In the present instance, both the inner and outer sections are formed of wood. and the outer section is coated or otherwise enveloped in a moisture resisting substance so as to render the same imper- VlOllS to moisture. The inner section is so fashioned that the grain thereof extends transversely thereof or substantially parallel to the axis of the casing so as to facilitate flexing of the section in the desirable direction. As previously stated, both sections are united together throughout the length thereof and tendency of separation of these sections is reduced by fashioning registering recesses in adjacent faces of the same to form a series of transverse openings 38 in the device 14. Incidentally, by fashioning cooperating recesses in the sections aforesaid, flexing of the device is facilitated and the exposed area of the hygroscopic section is increased accordingly with the result that the action thereof is expedited. Thus, from the foregoing it will be obvious that I have provided a relatively simple and inexpensive hygroscopic device having engaging hygroscopic and nonhygroscopic sections formed of the same material so that the action thereof will not be impaired by temperature variations.

\Vhat I claim as my invention is:

1. A laminated hygroscopic element having a hygroscopic section and a non-hygroscopic section united to the section aforesaid and having registering recesses in the contacting faces thereof.

2. A laminated hygroscopic element comprising arcuate hygroscopic and non-hygroscopic sections formed of the same material, said sections having adjacent faces united together and provided with spaced registering recesses as and for the reasons set forth.

3. A laminated hygroscopic element comprising a non-hygroscopic section and a hygroscopic section formed from the same material as the non-hygroscopic section and provided with recesses in one face thereof for increasing the exposed area of the same.

4. A laminated hygroscopic element comprising a non-hygroscopic section and a hygroscopic section secured to the section aforesaid and having transverse recesses in one side thereof for increasing the exposed area of the same and for facilitating flexing of the element.

5. A hygroscopic element including two straps of the same material having contacting longitudinal edges secured together and provided with opposed recesses at the joint therebetween, one of said straps being pervious to moisture and the other of said straps being impervious to moisture.

6. A hygroscopically responsive device having two sections fashioned from the same material, one ofsaid sections being exposed and pervious to moisture, the other of said sections being enveloped in a moisture resisting substance so as to be impervious to moisture, adjacent faces of said sections having registering recesses therin providing a series of spaced openings at the joint between said sections, facilitating the flexing of the device and increasing the sensitiveness thereof.

7. A laminated hygroscopic element operated solely by variations in the moisture content thereof, comprising flexible hygroscopic and non-hygroscopic sections formed section and a hygroscopic section, said sections bein of uniform length and secured together t roughout their len th, said sections having opposed recesses for increasing the exposed area of the same and for facilitating flexing of the element.

10. A hygroscopic element operated sole- 1 by variations in the moisture content tiiereof, including two straps of the same material of uniform length having contacting longitudinal edges secured together and provided with opposed recesses at the joint therebetween, one of said straps being pervious to moisture and the other of said straps being impervlous to molsture.

CHARLES F. WARRICK. 

